Williams, 21, is yet to make a first team appearance for Crewe but is highly rated in terms of Welsh football circles and beyond and Martinez would like him at Swansea as backup to Dorus De Vries with David Knight seemingly unlikely to return to the Liberty next season.
The young goalkeeper has already attracted interest from Bolton, Blackburn, Sunderland, Derby and West Ham despite his lack of experience which gives some indication of his abilities
Williams, who stands at 6 ft 4 would fit the bill of Welsh talent that Roberto says he would like to add where possible and provides a decent alternative to De Vries which again is something that we have stated this summer we need.